1. Field of the Invention
The present invention generally relates to the provision of and usage of decision support information relating to selective heart pacing of implantable medical devices.
2. Description of the Prior Art
Lately a very hot topic within the field of implantable medical heart devices has been the promotion of intrinsic ventricular activity as far as possible, for instance when using so-called DDD pacemakers. When such a DDD pacemaker is implanted in, for example, a patient with atrioventricular (AV) block II or III, the DDD mode operation induces a situation very similar to left bundle branch block (LBBB) which in the long run may cause heart failure. As a consequence, there has been a trend to provide pacemakers with algorithms that minimize ventricular pacing. Such algorithms are, for instance, known as Ventricular Intrinsic Preference (VIP™) by St. Jude Medical, Managed Ventricular Pacing (MVP™) by Medtronic and AAIsafeR™ by Sorin.
These prior art algorithms work slightly differently but all have similar objectives—if an atrial event (P-wave) will lead to ventricular contraction, it should be left alone but if it does not invoke a ventricular contraction, the ventricle should be paced. The problem is that it is not known beforehand whether the P-wave will be blocked or not. In order to deal with this problem, the algorithms basically every now and then withhold the atrium triggered pacing and monitor the intrinsic AV interval.
However, every time the algorithms “listen” for intrinsic conduction, they let the heart perform in a non-optimal way if no conduction took place within an acceptable time period. This means that the long AV delays that will indeed occur during such listening periods with inferior conduction may introduce complications, such as non-physiologic PR intervals, pacemaker-mediated tachycardia and artificially limited maximum tracking rates as discussed in Kenneth A. Ellenbogen, “Minimizing right ventricular pacing with a new pacing algorithm for implantable pacemakers and defibrillators: ADI mode”, EP Lab Digest, 6(3):18-21, March 2006.